The present invention relates to a heavy metal removal system which is useful in the removal of metal ions in aqueous solution.
Various disclosures exist in the art which illustrate clay-supported systems for the removal of undesired pollutants from aqueous solution (e.g, from industrial waste streams), including the following:
U.S. Pat. No. 4,740,488 to H. S. Fogler et al. forms such a system by the treatment of an expanded smectite clay with an excess of a solution of hydroxy-aluminum.
U.S. Pat. No. 4,866,018 to D. R. Elliot discloses organophilic clays made from a smectite type clay, a quaternary ammonium compound, and a zirconium-aluminum organic complex.
U.S. Pat. No. 4,916,095 to H. S. Fogler et al. forms a modified clay sorbent by treatment of an expanded smectite clay, such as montmorillonite, with highly charged inorganic cations which will exchange with hydrated cations in the expanded clay, followed by the reaction of the resulting product with a cationic surfactant.